Data center sites and colocation centers in and around New York City are struggling to stay online with varying degrees of success. And there are reports of intermittent issues with undersea cables crossing the Atlantic Ocean.

Hurricane Sandy continued to take a toll on internet infrastructure in New York City and beyond on Tuesday.

There were sporadic issues with undersea cable Atlantic Crossing-2 (or AC-2), sources said. These cables are the main data lifeline between continents.

Telx reported that most of its New York and New Jersey data centers were on generator power as of 9:30 a.m. EDT.

As feared, 75 Broad Street, which houses several data centers in the low-lying Zone A of Manhattan, was severely impacted, affecting Internap,Peer 1 and other providers.

INIT7, a Swiss provider of IPv6 infrastructure, was affected by a storm-related power outage at Equinix’ 8th Avenue facility in Manhattan. The company also reported connectivity issues to Miami and Los Angeles that have since been resolved.

Equinix reported widespread issues with its data centers in the areas around NYC, but said they all have 48 hours of fuel

A Navisite data center in Manhattan’s Zone A is also running on generators. It has refueled and has enough to las 72 hours and will refuel as needed.

The specter of trouble with the undersea cables could be a huge deal, although experts said that there is so much redundancy that much of the risk is mitigated. There were some reports attributed to cable operators who said they had experienced power issues but back-up generators prevented service disruption.

Carriers and ISPs use the cables to pump data across the Atlantic. Two of the major gateways are in Brookhaven, N.Y., (on Long Island) and in northern New Jersey, where the cables come ashore. “Given the duration and strength of this storm, you have to worry about the cables getting disrupted,” said an exeutive with a data center company who did not want to be named. He said problems with the cables is “ the kind of thing companies will keep close to the vest. If either AC-1 or AC-2 were to go out there would be major, major issues.”